Lol what? Which EU Server were you on?

Pf etiquette in EU is like this most of the time:

-You are completely new, just want a first look in the fight? Open for all players.

-You are at a specific prog point but not ready to clear yet? Open to all players, but specify your prog point in the pf info.

-You are ready to clear and open a clear party? Your choice: open it to all players with the specifics in the info that it's a clear party or open it only for ppl who cleared to help you. Most people I've seen will do the first option, though.

-You want a simple reclear or mechanic cleanup ? Open it to people who cleared it already and specify in info, so you get a higher chance to get the training you actually want.

-You want to farm efficiently? Open only for people who cleared.

At the end, it's every party leaders own choice. Their party, their rules. They chose the strat, they chose the iLvl, they chose the requirements.
And you can choose, which party you join. It's as simple as that.